lkml.org 
[lkml]   [2020]   [Nov]   [23]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 5.4 111/158] efi/x86: Free efi_pgd with free_pages()
    Date
    From: Arvind Sankar <nivedita@alum.mit.edu>

    [ Upstream commit c2fe61d8be491ff8188edaf22e838f819999146b ]

    Commit

    d9e9a6418065 ("x86/mm/pti: Allocate a separate user PGD")

    changed the PGD allocation to allocate PGD_ALLOCATION_ORDER pages, so in
    the error path it should be freed using free_pages() rather than
    free_page().

    Commit

    06ace26f4e6f ("x86/efi: Free efi_pgd with free_pages()")

    fixed one instance of this, but missed another.

    Move the freeing out-of-line to avoid code duplication and fix this bug.

    Fixes: d9e9a6418065 ("x86/mm/pti: Allocate a separate user PGD")
    Link: https://lore.kernel.org/r/20201110163919.1134431-1-nivedita@alum.mit.edu
    Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
    Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    arch/x86/platform/efi/efi_64.c | 24 +++++++++++++-----------
    1 file changed, 13 insertions(+), 11 deletions(-)

    diff --git a/arch/x86/platform/efi/efi_64.c b/arch/x86/platform/efi/efi_64.c
    index e39c930cfbd1e..5283978181103 100644
    --- a/arch/x86/platform/efi/efi_64.c
    +++ b/arch/x86/platform/efi/efi_64.c
    @@ -217,28 +217,30 @@ int __init efi_alloc_page_tables(void)
    gfp_mask = GFP_KERNEL | __GFP_ZERO;
    efi_pgd = (pgd_t *)__get_free_pages(gfp_mask, PGD_ALLOCATION_ORDER);
    if (!efi_pgd)
    - return -ENOMEM;
    + goto fail;

    pgd = efi_pgd + pgd_index(EFI_VA_END);
    p4d = p4d_alloc(&init_mm, pgd, EFI_VA_END);
    - if (!p4d) {
    - free_page((unsigned long)efi_pgd);
    - return -ENOMEM;
    - }
    + if (!p4d)
    + goto free_pgd;

    pud = pud_alloc(&init_mm, p4d, EFI_VA_END);
    - if (!pud) {
    - if (pgtable_l5_enabled())
    - free_page((unsigned long) pgd_page_vaddr(*pgd));
    - free_pages((unsigned long)efi_pgd, PGD_ALLOCATION_ORDER);
    - return -ENOMEM;
    - }
    + if (!pud)
    + goto free_p4d;

    efi_mm.pgd = efi_pgd;
    mm_init_cpumask(&efi_mm);
    init_new_context(NULL, &efi_mm);

    return 0;
    +
    +free_p4d:
    + if (pgtable_l5_enabled())
    + free_page((unsigned long)pgd_page_vaddr(*pgd));
    +free_pgd:
    + free_pages((unsigned long)efi_pgd, PGD_ALLOCATION_ORDER);
    +fail:
    + return -ENOMEM;
    }

    /*
    --
    2.27.0


    \
     
     \ /
      Last update: 2020-11-23 14:41    [W:4.189 / U:0.308 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site